Negative electrode plate and battery

Abstract

Disclosed are a negative electrode plate and a battery, the negative electrode plate includes a current collector and an active layer; the active layer is positioned on two opposite surfaces of the current collector; the active layer includes a first functional material; the content of the first functional material increases in a direction away from the current collector; the content of the first functional material in a first region of the active layer is less than the content of the first functional material in a second region of the active layer; the vertical distance from the first region to the current collector is less than the vertical distance from the second region to the current collector; and the first functional material includes at least one of a silicon-based material, a metal oxide, or a metal sulfide. The energy density and dynamics of the negative electrode plate are improved.

What is claimed is: 
     
         1 . A negative electrode plate, comprising a current collector and an active layer, wherein:
 the active layer is positioned on two opposite surfaces of the current collector;   the active layer comprises a first functional material;   a content of the first functional material increases in a direction away from the current collector; the content of the first functional material in a first region of the active layer is less than the content of the first functional material in a second region of the active layer;   a vertical distance from the first region to the current collector is less than a vertical distance from the second region to the current collector; and   the first functional material comprises at least one of a silicon-based material, a metal oxide, or a metal sulfide.   
     
     
         2 . The negative electrode plate according to  claim 1 , wherein the silicon-based material comprises at least one of silicon particles, silicon carbon composite, silicon oxide, or silicon alloy. 
     
     
         3 . The negative electrode plate according to  claim 1 , wherein the metal oxide comprises at least one of tin oxide, nickel oxide, cobalt oxide, antimony oxide, or bismuth oxide. 
     
     
         4 . The negative electrode plate according to  claim 1 , wherein the metal sulfide comprises at least one of tin sulfide, nickel sulfide, cobalt sulfide, antimony sulfide, or bismuth sulfide. 
     
     
         5 . The negative electrode plate according to  claim 1 , wherein the active layer further comprises a second functional material; a content of the second functional material increases in a direction away from the current collector; and the content of the second functional material in the first region is less than the content of the second functional material in the second region. 
     
     
         6 . The negative electrode plate according to  claim 5 , wherein a conductivity of the second functional material is greater than that of any other conductive agents in the active layer except for the second functional material. 
     
     
         7 . The negative electrode plate according to  claim 5 , wherein the second functional material comprises at least one of carbon nanotube, graphene, gold fiber, or silver fiber, and a conductive agent except for the second functional material comprises at least one of conductive carbon black, acetylene black, Ketjen black, conductive graphite, conductive carbon fiber, metal powder, or carbon fiber. 
     
     
         8 . The negative electrode plate according to  claim 1 , wherein the active layer at least comprises a first sub-active layer, a second sub-active layer, and a third sub-active layer;
 the first sub-active layer is positioned on a side surface of the current collector; the second sub-active layer is positioned on the first sub-active layer; the third sub-active layer is positioned on the second sub-active layer; and   the content of the first functional material increases in a direction from the first sub-active layer to the third sub-active layer.   
     
     
         9 . The negative electrode plate according to  claim 8 , wherein the active layer further comprises a second functional material; and a content of the second functional material increases in a direction from the first sub-active layer to the third sub-active layer. 
     
     
         10 . The negative electrode plate according to  claim 8 , wherein the first sub-active layer comprises a first active substance, a first conductive agent, and a first binder; and a mass percentage range ratio between the first active substance, the first conductive agent, and the first binder is (70 wt %-99 wt %):(0.5 wt %-15 wt %):(0.5 wt %-15 wt %). 
     
     
         11 . The negative electrode plate according to  claim 9 , wherein the second sub-active layer comprises a second active substance, a second conductive agent, and a second binder; and a mass percentage range ratio between the second active substance, the second conductive agent and the second binder is (70 wt %-99 wt %):(0.5 wt %-15 wt %):(0.5 wt %-15 wt %);
 the second active substance comprises the first functional material accounting for A 1 %; and the second conductive agent comprises the second functional material accounting for A 2 %.   
     
     
         12 . The negative electrode plate according to  claim 11 , wherein the first functional material accounting for A 1 % is 0 wt % to 30 wt % at least one of a silicon-based material, and the second functional material accounting for A 2 % is 0 wt % to 15 wt % a carbon nanotube. 
     
     
         13 . The negative electrode plate according to  claim 11 , wherein the second active substance comprises a carbon-based silicon-doped material; and the second conductive agent comprises the second functional material and at least one of conductive carbon black, acetylene black, Ketjen black, conductive graphite, conductive carbon fiber, metal powder, or carbon fiber. 
     
     
         14 . The negative electrode plate according to  claim 11 , wherein the second active substance comprises silicon-doped graphite; the second conductive agent comprises conductive carbon black and carbon nanotubes; and the second binder comprises styrene-butadiene latex. 
     
     
         15 . The negative electrode plate according to  claim 11 , wherein the third sub-active layer comprises a third active substance, a third conductive agent, and a third binder; and a mass percentage range ratio between the third active substance, the third conductive agent and the third binder is (70 wt %-99 wt %):(0.5 wt %-15 wt %):(0.5 wt %-15 wt %);
 the third active substance comprises the first functional material accounting for B 1 %; the third conductive agent comprises the second functional material accounting for B 2 %; B 1  is greater than A 1 ; and B 2  is greater than A 2 .   
     
     
         16 . The negative electrode plate according to  claim 15 , wherein the first functional material accounting for B 1 % is 0 wt % to 30 wt % at least one of a silicon-based material, a metal oxide, or a metal sulfide, wherein B 1  is greater than A 1, and 0 wt % is excluded; and the second functional material accounting for B 2 % is 0 wt % to 15 wt % carbon nanotubes, wherein 0 wt % is excluded. 
     
     
         17 . The negative electrode plate according to  claim 15 , wherein the third active substance comprises a carbon-based silicon-doped material; and the third conductive agent comprises the second functional material and at least one of conductive carbon black, acetylene black, Ketjen black, conductive graphite, conductive carbon fiber, metal powder, or carbon fiber. 
     
     
         18 . The negative electrode plate according to  claim 15 , wherein the third active substance comprises silicon-doped graphite; the third conductive agent comprises conductive carbon black and carbon nanotubes; and the third binder comprises styrene-butadiene latex. 
     
     
         19 . The negative electrode plate according to  claim 8 , wherein the first sub-active layer, the second sub-active layer, and the third sub-active layer have a same thickness; or
 a thickness of any layer of the second sub-active layer and the third sub-active layer is less than a thickness of the first sub-active layer; or   a thickness of the third sub-active layer is less than a thickness of the second sub-active layer, and the thickness of the second sub-active layer is less than a thickness of the first sub-active layer.   
     
     
         20 . A battery, comprising the negative electrode plate according to  claim 1 .